But today I found an article[3]. And finally I could download. Let me write the way here.
cpython(python) has repositories for Mercurial (primary), Github(mirror).
But in the git repository, the tags information is not kept. And that is not convenient to install specified version’s python.

Create empty hg environment.

$ hg init cpython
$ cd cpython

Download information one by one, like a fetch.
Seeing hg log | less after each hg pull.